Not to be outdone by rival Verizon and AT&T which rolled out their fourth-generation Long-Term Evolution (LTE) networks to 29 and five new U.S. cities this week, respectively, T-Mobile USA today announced that its iPhone-friendly HSPA+ service on the 1900MHz band is launching in fourteen new metropolitan areas.

The carrier says these markets can take advantage of voice and data enhancements, improved signal strength and in-building coverage. The $4 billion network modernization plan announced ten months ago already enhanced coverage for more than a hundred million people, T-Mobile said…

The carrier is also enhancing the service in areas like parts of Los Angeles and San Diego:

T-Mobile will continue to expand the network advancements in these metro areas and has begun coverage enhancements in additional areas, including parts of Los Angeles and San Diego, where customers are already experiencing improved coverage and unlocked iPhone “speed sightings” on T-Mobile’s 4G network.

AT&T earlier this week rolled out LTE in Green Bay, Springfield, Tucson, Melbourne and Oxford and is now covering 125 metropolitan markets with the high-speed data service.

Verizon claims its LTE is now available in 470 markets to more than 250 million people in the United States.

Sprint, which just completed its acquisition of Clearwire, is looking to have its LTE network up and running in 31 cities by mid-2013.

In related news, René Obermann, the CEO of Deutsche Telekom, T-Mobile USA’s parent company, in a statement issued Thursday said he was stepping down as CEO. It was “a surprise departure”, Bloomberg writes.

Obermann apparently asked for his contract to be terminated, effective December 31, 2013. The German telco’s finance chief Tim Höttges will step up as the interim CEO in 2013, removing the “interim” prefix on January 1, 2014.